Heating head and mask apparatus

ABSTRACT

Heating head and mask apparatus are provided for producing electrically conductive heated glass panels that may be used to warm objects or insure unobstructed viewing through glass by removing moisture. The heating head and mask apparatus utilizes either a circularly rotating or an inline heating head and mask apparatus, which deposits conductive metal bus bars into electrical contact with electrically conductive-coatings that are-disposed on the glass panels.

RELATED APPLICATIONS

[0001] This application claims the benefit, under 35 U.S.C. § 119(e), ofU.S. Provisional Patent Applications Ser. No. 60/339,409, filed Oct. 26,2001 under 35 U.S.C. § 111(b), and Ser. No. 60/369,962, filed Apr. 4,2002 under 35 U.S.C. § 111(b), which applications are incorporatedherein in their entirety.

[0002] This application is a divisional application of and claimsbenefit, under 35 U.S.C. § 120, of pending U.S. patent application Ser.No. 10/256,391, filed Sep. 27, 2002, which application is incorporatedherein in its entirety.

BACKGROUND OF THE INVENTION

[0003] The present invention generally relates to electricallyconductive heated glass panel assemblies and control systems, forwarming objects and for the removal of moisture on such glass panelassemblies. More particularly, the present invention relates toregulating the flow of current in low emissivity (low E) conductivemetal oxide coatings on insulated glass (IG) panels and laminatedstructures. Most particularly, the present invention deals with theelectrical connectivity to insulated glass panels, laminated structures,and combinations thereof.

[0004] At the present time, heating, cooking, moisture control, and theelectrical control of such processes and activities do not take fulladvantage of the potential of the use of coated glass. In general,utilizing thin-film coatings to produce heat in a glass panel is anestablished concept. However, in the past, the film depositiontechniques, such as those used in spray coating, were not precise, whichresulted in non-uniform coatings and consequently imprecise heating.Recently, the depositing of the coatings has improved, for example,through the use of chemical vapor deposition (CVD), but the electricalcontrol of and connectivity to the coatings has not.

[0005] An application of heated glass that has seen these changes overthe last thirty years is, for example, the commercial refrigerator andfreezer doors in supermarkets, where a tin oxide coating is disposed onone of the interior surfaces of an IG panel and where an electriccurrent is dissipated in the tin oxide to provide heat to raise theglass temperature above the dew point. On such doors, the heateliminates the formation of condensation, so that employees andcustomers can view the refrigerator/freezer contents after individualshave opened and closed the doors.

[0006] However, non-uniform coatings and traditional electrical controlmethods result in wasted energy, produce hot and cold spots on theglass, and can result in safety hazards should the glass break andexpose the current-carrying film. This approach could benefit fromcontrol opportunities that exist using the current state of controltechnology.

[0007] For transportation applications, where heated windows and mirrorsprovide drivers and occupants of land, air, and water vehicles unimpededviewing by the removal of condensation, breakage of the electricallyheated glass panels can also result in electrical safety problems.Underwriters Laboratories (UL) has expressed interest in improving thebreakage of electrically heated glass panels and consequently theexposure of live electrical conductors within the glass.

[0008] In convenience stores and delicatessens, sandwiches and otherfood items are kept warm in glass enclosed food warmers, through the useof base electrical element heaters. The use of glass enclosures-doesallow the contents to be seen, but the use of only base-electricalribbon element heaters does not allow for radiant heating techniquesthat would be advantageous for the warming of food items from an areaabove the food items.

[0009] Commercial buildings, sports stadium skyboxes, sloped glazing inatria, canopies, and general fenestration applications, could benefitfrom the use of electrically heated glass panels, but the underlyingreason for the reluctance to adopt these technologies in architecturalapplications is the lack of an integrated connection circuit and asystems approach to these applications. Expanding the adoption of thesetechnologies, however, is hampered by the complexity of safely,reliably, and cost effectively combining glass and electricity.

[0010] There have been many methods advocated to electrically controlheated glass panels. Among them are: direct connection to 120V AC power,use of step-down transformers, resistor-capacitor (RC) networks, triacs,and control circuits that directly drive resistive loads. All of theseapproaches have their benefits and also their disadvantages.

[0011] Some of the problems that must be overcome by the electricalcontrols are: (a) electrical shock potential, (b) circuitry componentsreleasing significant heat to the overall system, (c) overload of theintegrated connection circuits that supply the power to the panels, (d)bulkiness of the parts used in the control method, (e) lack of mountingspace for the parts, (f) electrical interference generated by thecontrol method, (g) lack of predictability and complexity of the controlmethod, and (h) overall serviceability and costs.

[0012] The RC network approach that is taught in U.S. Pat. No. 5,852,284to Teder et al. uses an RC circuit in series with the conductive coatingon the glass to match the power supply with the characteristics of theglass assembly. Typically the value of the capacitor can be chosen forthe desired power density via known electrical engineering calculations.In this method, the capacitor functions by changing the phase anglebetween the voltage and current of the applied AC voltage, henceregulating the power dissipation.

[0013] Disadvantages of this method are that capacitors of the requiredvalue are: (1) physically large and may be expensive, (2) when acapacitor fails, the full line voltage may be applied across the coatedglass, (3) there is no integrated protection using such a method, soover-current protection must be provided, (4) handling many differentapplications is problematic, such that either a stock of a large numberof different values of capacitors would be required or a large number ofseries-parallel networks must be constructed, which can also complicatethe issues of required space and cost, and (5) the varying electricalphase angle may present power quality problems.

[0014] The use of triacs has shown promise as a way to vary the currentthat is applied to electrically coated sheets of glass. Examples oftriac use are U.S. Pat. No. 4,260,876 to Hochheiser and U.S. Pat. No.5,319,301 to Callahan et al. However, this use must overcome thenegative effects of the triacs generating high peak currents, highharmonic distortion, and electromagnetic interference (EMI).

[0015] The use of electrical control circuits to operate the triacs,which in turn controls the current through the electrically conductiveheated glass panel assembly and control systems, has the potential tominimize these negative effects, but to-date it has not been able toaccomplish that task. Consequently, the application of triacs has notfully been able to solve the aforementioned problems in the control ofelectrically conductive heated glass panel assembly systems.

[0016] Also, the interconnections between the parts of an electricallyconductive heated glass panel assembly and control system have typicallybeen treated as individual parts and not as part of an overall system.In some cases, the bus bars have been screen-printed or fired conductivesilver frits. These are difficult and expensive to print and difficultto solder external leads to, where special solder is required.

[0017] Further, various metallic tapes, including copper, have beenattached to glass using adhesives but these connections exhibit pooradhesion to the glass. Also, rigid electrical terminations at the edgeof the glass result from these methods of applying the bus bars, whichmakes them vulnerable to mechanical flexing, can expose them tocondensation, and typically are expensive.

[0018] U.S. Pat. No. 2,235,681 to Haven et al., teaches the attaching ofmetal bus bars to a glass sheet as it applies to structural solderelements-but not for electronic control systems.

[0019] Producers of crystalline solar cell technology (also referred toherein as photovoltaic technology) have been seeking ways to depositmetal-on-glass. U.S. Pat. No. 6,065,424 to Shacham-Diamand et al.,teaches thin metal film coatings sprayed onto glass by the use of anaqueous solution and subsequent annealing of the coatings. In U.S. Pat.No. 4,511,600 to Leas, a conductive metal grid is deposited atop acrystalline solar cell by the use of a mask and orifices (without theuse of gas or air pressure to impart dispersion or velocity to the metalparticles). The '600 patent also advocates the use of a powdered metalthat is heated to a molten temperature in a refractory crucible.

[0020] In U.S. Pat. No. 4,331,703 to Lindmayer, a conductive metal isflame sprayed onto a silicon solar cell. In U.S. Pat. No. 4,297,391,also to Lindmayer, particles of a material are formed at a temperaturein excess of the alloying temperature of the material and the silicon,and then the two are sprayed onto the surface of the glass at adistance, which causes the material and the silicon to firmly adhere tothe surface. The '391 patent also teaches the use of a mask.

[0021] Currently, the control of electricity to electrically conductiveglass panels centers primarily on control of the heating elements andnot on monitoring system parts or the entire heating system for safety,power matching, or the like. For wiring installation purposes of theglass panels, it is common for holes to be drilled in the glass panelsat the time of manufacturing and in the framework at the time ofinstallation as well as for termination of wiring that is done in thefield.

[0022] When the assembly of the electrical panels is completed, some ofthe controls, wiring, and associated parts are visible to users of thesepanel systems. Since power supply matching for each application isstatically performed, the changing of system variables aftermanufacturing is, at best, cumbersome, while monitoring of systemoperating conditions is nearly nonexistent.

[0023] Termination of system wiring to existing facility electricalservices, as well as on-site glazing operations, is not done with atotal systems approach in mind. Thus those skilled in the art continuedto seek a solution to the problem of how to provide a betterelectrically conductive heated glass panel assembly and control system,and a method for producing the panels.

SUMMARY OF THE INVENTION

[0024] The present invention relates to depositing conductive metal onsheets of dielectric substrate materials, for example, bus bars on asurface of glass or on an electrically conductive coating that isdisposed on a major surface of a glass sheet, the bus bars beingdeposited by way of a heating head and mask apparatus. In conjunction,the present invention relates to depositing and electrically contactingmetallic tabs, which extend from the peripheral edge of the glass sheetto the metal bus bars, to the bus bars thus allowing robust externalelectrical connection to the electrically conductive coatings.

[0025] The glass sheet, so constructed, could be assembled with at leasta second glass sheet and a polymeric interlayer therebetween to form alaminated panel. In addition, the glass sheet could be assembled with atleast a second glass sheet and a T-shaped spacer-seal, an E-shapedspacer-seal, or the like disposed around a periphery therebetween toform an insulated glass panel.

[0026] Heated glass panels, as so described, may be mechanically andelectrically interconnected to form a heated glass panel assembly andcontrol system that would further comprise at least onecondition-sensing means capable of generating a condition signal, acurrent-switch, and a solid-state controller capable of reading thecondition signal for controlling the current-switch. As a result, thecurrent-switch would control electrical current in the heated glasspanel, thus controlling the desired heating of the heated glass panel.

[0027] The present invention employs methods of depositing a conductivemetal bus bar on an electrically conductive coating that is disposed ondielectric substrate material, for example, a glass sheet, the methodsof depositing comprising: 1) if edge deletion is required, preciselythermally shocking or edge masking and heating a first area of thecoating with a coating heater, forming a residue of the coating in thefirst area, removing the residue from the first area with a coatingremover, and then regardless of whether edge deletion is required, 2)masking a second area of the coating with an inner mask and an outermask, where the second area is defined therebetween or by masking acentral area of the substrate sheet thus defining the second area asopposing edges, 3) heating the second area with a reducing flame, 4)feeding a conductive metal into a metal feeding and heating device, soas to melt the metal, and propelling particles of the molten metal ontothe second area.

[0028] Further objects and advantages of the present invention will beapparent from the following description and appended claims, referencebeing made to the accompanying drawings forming a part of aspecification, wherein like reference characters designate correspondingparts of several views.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1a is a schematic of an overview of an integrated connectioncircuit in accordance with the present invention;

[0030]FIG. 1b is a schematic of an interconnection of an electricallyconductive heated glass panel and a first glazing channel in accordancewith the present invention;

[0031]FIG. 1c is a schematic of an interconnection of an electricallyconductive heated glass panel and a second glazing channel in accordancewith the present invention;

[0032]FIG. 2 is a schematic of a current-switch circuit that employstriacs in accordance with the present invention;

[0033]FIG. 3 is a cross sectional view of an installation of anelectrically conductive heated glass pane land a base setting block,within a first glazing channel in accordance with the present invention;

[0034]FIG. 4a is a cross sectional view of an electrically conductiveheated glass panel and a base setting block in a partially closedconnection position in accordance with FIG. 3;

[0035]FIG. 4b is a cross sectional view of an electrically conductiveheated glass panel and a base setting block in a fully claspedconnection position in accordance with FIG. 4a;

[0036]FIG. 4c is a perspective view of an electrically conductive heatedglass panel and a connection clip in a fully clasped connection positionin accordance with FIG. 4a;

[0037]FIG. 5 is a side view of electrical and mechanical connections ofan electrically conductive heated glass panel in accordance with thepresent invention;

[0038]FIG. 6a is a side view of an interconnection of multipleelectrically conductive heated glass panels in accordance with thepresent invention;

[0039]FIG. 6b is a side and bottom view of a wiring method showing apush-on connector and interconnection wires in accordance with thepresent invention;

[0040]FIG. 7 is a cross sectional view of an installation of anelectrically conductive heated glass panel within a second glazingchannel in accordance with the present invention;

[0041]FIG. 8a is a cross sectional view at a peripheral edge of aninsulated glass panel where a T-shaped spacer seal unit and a panelframe are employed in accordance with the present invention;

[0042]FIG. 8b is a cross sectional view at the peripheral edge of theinsulated glass panel where an E-shaped spacer seal unit is employed inaccordance with the present invention;

[0043]FIG. 9 is a cross sectional view at a peripheral edge of alaminated glass panel in accordance with the present invention;

[0044]FIG. 10a is a diagramatic view of a circularly rotating heatinghead and mask apparatus in accordance with the present invention;

[0045]FIG. 10b is a diagramatic view of an inline heating head and maskapparatus in accordance with the present invention;

[0046]FIG. 10c is a perspective view of a belt based inline heating headand mask apparatus in accordance with the present invention;

[0047]FIG. 10d is a top plan view of the belt based inline heating headand mask apparatus of FIG. 10c;

[0048]FIG. 10e is a side plan view of the belt based inline heating headand mask apparatus of FIG. 10c;

[0049]FIG. 11 is a perspective view of a warming oven in accordance withthe present invention; and

[0050]FIG. 12 is a cross sectional view of an oven door panel inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0051] The present invention employs an integrated connection circuit18, as shown in FIG. 1a, where electrical current (I) passes through acoating that is disposed on a sheet of a dielectric material, forexample, an electrically conductive heated glass panel 20, to generateheat that can be used for warming, cooking, moisture control, and thelike. The panel 20 may be realized within the present invention as alaminated panel 40, an insulated glass panel 30, or a combinationthereof. The present invention has been found to apply to sheets thatare dielectric substrate materials other than glass, for example,ceramic and glass-ceramic materials.

[0052] In order to control the electrical current (I) flowing throughthe electrically conductive heated glass panel 20, a solid-statecontroller 16, for example, a programmable application-specificintegrated circuit (ASIC) chip, would monitor inputs like a signal (S)from a condition-sensing means, for example, a condition sensor 21.Examples of conditions that could be sensed by the condition sensor 21include, but are not limited to, temperature, moisture, voltage, andcurrent. Also, the signal (S) may be obtained from voltages taken acrossthe bus bars 22. If those voltage signals (S) are taken rapidly by wayof the controller 16 the voltages can be converted into an indication ofthe temperature of the panel 20.

[0053] Another way the present invention may obtain a signal (S) isthrough the placement of a thermostatic switch (not shown) on a majorsurface 33 of the panel 20, wherein if the temperature of the surface 33reaches a first setpoint, the thermostatic switch is electricallyconductive and if the surface temperature reaches a second setpoint thethermostatic switch is electrically nonconductive.

[0054] Upon receiving the signal (S), the solid-state controller 16might respond to the signal (S) by commanding various operations, likecontrolling a current-switch circuit-15, for example, a triac circuit 17shown in FIG. 2, to be operated in a zero-axis crossing manner.

[0055] Consequently, the solid-state controller 16 would preciselycontrol heating of the electrically conductive heated glass panel 20.

[0056] By operating the triac circuit 17 in the zero-axis crossingmanner, problems such as harmonic distortion and electromagneticinterference (EMI) are overcome. Use of the zero-axis crossing manneralso minimizes capacitive coupling 20, and leakage current problemsassociated with using dielectric material with electrical currents (I).

[0057] In the present invention, the current-switch circuit 15, undercontrol of the solid-state controller 16, would provide opticalisolation (as shown in FIG. 2 by components U2 and U3) in thecurrent-switch output control lines. In turn, this minimizes electricalinterference to control circuit 25, the electrically-conductive heatedglass panel 20, and external sensors and controls 28.

[0058] In addition, the solid-state controller 16 allows the presentinvention to usefully integrate disparate parts of the electricallyconductive heated glass panel 20 in a more comprehensive manner than RCnetworks and other control methods can provide. This allows thesolid-state controller 16 to more effectively control appliances, forexample, a heating element, vehicles, or building functions by way ofthe external sensors and controls 28, while employing wired or wirelessdevices. System variables are easily changed by a use of the solid-statecontroller 16.

[0059] Further, the solid-state controller 16 would provide impedancematching for the current-switch circuit 15, which would result in morecomplete system safety by monitoring voltage and current levels that aretoo high and too low. This would protect users and system components,for example, by shutting down associated equipment. Other forms ofelectrically conductive heated glass panel controls may not be able toprovide this capability.

[0060] Additionally, regarding glass breakage safety, the solid-statecontroller 16 is capable of monitoring the current (I) passing threw thecoating 44 on the panel 40. If the current (I) were to cease in thecoating 44 then the panel 40 may have broken. Also a strip switch 26 maybe applied that would be sealed within the laminated glass panel 40, asfurther illustrated in FIG. 9. If the uncoated glass sheet 32 were tobreak then the current (I) through the strip switch 26 would cease,wherein the solid-state controller 16 would sense a change in thecurrent (I), would cut off power to the damaged laminated glass panel40, and would signal users of the integrated control circuit 18 of suchan event, so as to keep the users from being exposed to an electricalshock and physical cuts due to broken glass.

[0061] By operating the current-switch circuit 15 in the zero-axiscrossing manner, the solid-state controller 16 does not requirecontrolling capacitors. This reduces cost, weight, and number of systemcomponents, which consequently reduces the necessary space to mountthem. In addition, the solid-state controller 16 provides electricalisolation for system components that other control circuits cannotprovide and the solid-state controller 16 provides power sourceconditioning, which better manages electrical component requirements.

[0062] As a result, maintenance replacement inventories are simplified,field adjusting of system devices and set points are reduced, as well asassociated costs. Since the solid-state controller 16 can read internaland external system signals (S), precision control of glass temperaturescan be provided, system performance can be monitored, and early warningof system problems can be detected that other electrically conductiveheated glass panel control methods cannot achieve.

[0063] To interconnect the electrically conductive heated glass panel 20to the current-switch circuit 15 and to interconnect a plurality ofelectrically conductive heated glass panels 20, a first glazing channel60 may be employed, as shown in FIG. 1b. Panel setting blocks 35, thatare disposed on the electrically conductive heated glass panels 20, matewith base setting indentations 43 to provide mechanical mounting for theelectrically conductive heated glass panels 20.

[0064] Further, portions of metal foil 39 a, 39 b are disposed withinthe electrically conductive heated glass panels 20, from a glass panelperipheral edge 37, up to a sight line 29, and onto metallic tabs 24.The metallic tabs 24 and foil 39 electrically connect to the firstglazing channel 60 by being clasped by connection clips 41, whichelectrically connect to channel conductors 27. Insulating sleeves 31 andthe channel conductors 27 provide means to allow the electricallyconductive heated glass panels 20 to be connected to additionalelectrically conductive heated glass panels 20. Note that the use ofmetal foil 39 as described here may be applied to other glazingchannels.

[0065] Consequently, the current-switch circuit 15 that controls theelectrical current (I) may allow the electrical current (I) to beconducted through the glazing channel 60, by way of the channelconductors 27 and the connection clips 41. Since the connection clips 41clasp the metallic tabs 24, the electrical current (I) enters theelectrically conductive heated glass panels 20 and passes through busbars 22 and coating 44, which is disposed on a coated glass sheet 34. Asa result, heat is generated within the electrically conductive heatedglass panels 20 for heating objects and removing moisture.

[0066] An alternative to the first glazing channel 60 of FIG. 1b is asecond glazing channel 60′, illustrated in FIG. 1c and with more detailin FIG. 7. The electrically conductive heated glass panel 20 ismechanically mounted to a channel frame 67 and electrically connected tothe metallic tabs 24 by way of spade connection 96 that is attached toan end of the channel conductor 27. The channel conductor 27 is in turnrouted through the channel frame 67 by way of a channel conduit 95 andconductor block 93 and then electrically and mechanically connected tothe interconnecting channel conductor 27 by conventional means. Glazingseal 23 is disposed in a second glazing channel cavity 59′ and in voidsthroughout the channel frame 67 to seal out moisture and dirt, and toprotect the parts of the second glazing channel 60′ from damage.

[0067] Consequently, the current-switch circuit 15 that controls theelectrical current (I) may allow the electrical current (I) to beconducted through the second glazing channel 60′. As a result, heat isgenerated within the electrically conductive heated glass panels 20 forheating objects and removing moisture. Both glazing channels 60, 60′would be applicable for photovoltaic applications.

[0068] It may be noted that conventional type K thermocouples orpossibly a thin film thermocouple like that disclosed in U.S. Pat. No.6,072,165 to Feldman (which is incorporated herein in its entirety) maybe used for temperature determination. An advantage of the presentinvention is that programming the solid-state controller 16 with thecoefficient of resistance of the electrically conductive heated glasspanel 20 and momentarily sampling voltages across sets of bus bars 22,the solid-state controller 16 could compare those voltages topredetermined thresholds (a.k.a., setpoints) so as to determine thetemperature of the panel 20. Thus the temperature of the panel 20 may becontrolled without the use of any thermocouple.

[0069] By using the controller 16 along with the type K thermocouple,the film thermocouple, or the voltage reading method temperaturesensing, a panel, for example, one installed in a sport stadium box,would not overheat, break, or cause damage, as other glass assemblieswould.

[0070] The solid-state controller 16, the condition sensors 21, thecurrent-switch circuit 15, the metallic tabs 24, direct current powersupplies 14 that are illustrated in FIG. 1a, along with conventionalwiring, insulating boots, terminal strips, direct current to alternatingcurrent inverter circuits, ground fault circuit interrupter (GFCI)circuit breakers, on-off alternating power source controls, connectionsto external sensors and controls 28, NEC electrical wiring terminationboxes and connecting wiring, the channel conduit 95, the conductorblocks 93, may all be placed in one or more of the panel frames 48,panel setting blocks 47, channel frames 67, or in conventional NECcontrol panels. This will result in advantageously placing the parts outof sight, while conserving space.

[0071] Referring to FIG. 3, there is shown a first glazing channel 60,which is an assembly of three subassemblies in accordance with an aspectof the present invention: (1) the laminated glass panel 40 (theinsulated glass panel 30 or combination laminated and/or IG panel may beemployed as well), (2) a base setting block 47, and (3) a glazingchannel base 58. In FIG. 3, the laminated glass panel 40 is shown havingthe metallic tab 24 and the metal foil 39 disposed within the interlayer46, where the metal foil 39 is disposed from the sight line 29 to theglass panel peripheral edge 37 and onto the exterior portions of themetallic tabs 24, so as to keep the metal foil 39 out of the sight ofusers.

[0072] As shown in FIG. 1b, a portion of the metal foil 39 a that isdisposed on a particular metallic tab 24 may not be in direct electricalcontact with another portion of metal foil 39 b, within the samelaminated glass panel 40. This separation of the portions of the metalfoil 39 a, 39 b may be required in order to allow the electrical current(I) to be conducted through one metallic tab 24 and its correspondingbus bar 22, the conductive coating 44, another bus bar 22 and itscorresponding metallic tab 24.

[0073] External to the laminated glass panel 40, both the metallic tab24 and the metal foil 39 are shown extending from the glass panelperipheral edge 37. The deposition of the metal foil 39 and the metallictab 24, as described, causes the two to be in electrical contact witheach other, thus providing a measure of redundancy. In addition, FIG. 3shows the metal foil 39 and the metallic tab 24 being mechanicallyclasped by opposing inside clasping surfaces 55 of a connection clip 41,the clasping by the clasping surfaces 55 being a result of a spring 52urging the connection clip 41 about a pivot 57.

[0074] The extension of the spring 52 is a result of a movement of theconnection clip 41 within the base setting block 47, wherein the basesetting block 47 is formed so as to define at least a widened portion ofa block cavity 51. As a result of the aforementioned movement, thelaminated glass panel assembly 40 and the base setting block 47 abut toform an assembly. Subsequently, the abutment of the laminated glasspanel 40 and the base setting block 47 are further abutted to a glazingchannel surface 53 that is positioned to define at least a portion of afirst glazing channel cavity 59 within a glazing channel base 58.

[0075] To further assure that the wiring of the laminated glass panels40 is hidden from the view of the user and to allow moisture to drainout and away from the laminated glass panels 40, wiring/drain holes 49may be provided in the glazing channel base 58, preferably at the timeof manufacturing, so as to minimize the need to drill holes in thelaminated glass panels 40 during installation in a structure or thelike.

[0076] Unbonded areas (UBAs) may form on the aforementioned assembly,which can result in: (a) moisture entering, (b) glass chipping, (c)glass swelling, and (d) electrical connections being adversely affected.In the present invention, a glazing seal 23 is preferably disposed inassembly voids to minimize the negative effects of UBA.

[0077] As illustrated in FIGS. 4a-4 c, there is shown the laminatedglass panel 40 (the insulated glass panel 30 or combination laminatedand/or IG panel may be employed as well) being brought into abutment andelectrical connection with the base setting block 47 and the connectionclip 41 in accordance with FIG. 3. FIG. 4a shows a cross sectional viewof a partially closed connection clip 41 where the spring 52 is onlypartially extended. Also shown is the laminated glass panel 40approaching the base setting block 47, wherein the attached metal foil39 and metallic tabs 24 are about to be clasped by the partially openconnection clip 41 and its partially extended spring 52.

[0078] As the laminated glass panel 40 and the connection clip 41 moveinto full attachment, the cross sectional view of FIG. 4b shows thecomplete clasping of the metal foil 39 and the metallic tabs 24 by theconnection clip 41 along with the full extension of the spring 52. Alsoshown in this view are the laminated glass panel 40 and the base settingblock 47 in full abutment.

[0079]FIG. 4c is a perspective view in accordance with FIG. 4a showingfurther details of the laminated glass panel 40 having the metal foil 39and metallic tab 24 fully clasped by the connection clip 41 whileshowing an extension of the channel connector 27 with insulating sleeve31 attached to the connection clip 41 at the pivot 57 of the connectingclip 41. The channel connector 27 along with the insulating sleeve 31,may act to interconnect a plurality of base setting blocks 47.Consequently, a plurality of laminated glass panels 40 would beinterconnected within the integrated connection circuit 18.

[0080] The above discussion on the interconnection of the laminatedglass panel 40, by way of the metal foil 39, the metallic tabs 24, theconnection clips 41, and the springs 52, in conjunction with the basesetting block 47, applies to glass solar panels as well.

[0081] Further, FIG. 5, in accordance with the present invention, showsa side view of the electrical and mechanical connection of the laminatedglass panel 40 (the insulated glass panel 30 or a combination laminatedand/or IG panel may be employed as well), where the metal foil 39 coversthe electrical connection for each metallic tab 24, thus providing themeasure of electrical redundancy, from within the laminated glass panel40, starting at the sight line 29, and then externally covering theextension of the metallic tabs 24.

[0082] Subsequently, the metallic tabs 24 mate with the connection clips41, which are embedded in the base setting block 47, as shown in FIG.1b. A mechanical connection between the laminated glass panel 40 and thebase setting block 47 is achieved by a mating of one or more panelsetting blocks 35 and one or more base setting indentations 43, as shownin FIGS. 1b and 5.

[0083] In accordance with the present invention, the combination ofFIGS. 6a and 6 b illustrate how an interconnect 80 uses multiple panelwiring 90 to interconnect multiple laminated glass panels 40. Channelconductors 27 and push-on connectors 54, in combination with the metalfoil 39 and the connection clips 41 provide ease and redundancy toaccomplish the interconnection of the multiple laminated glass panels40. These interconnection means complement the use of the channelconnectors 27 and the insulating sleeves 31 for interconnecting multiplelaminated glass panels 40, as discussed above.

[0084] In addition, FIG. 6a shows an application of a thermocouple 65, acircuit breaker 61, and a power switch 63, which act to monitortemperature conditions and to control power within the integratedconnection circuit 18. If the temperature of the laminated glass panel40 exceeds a setpoint temperature, as set within the circuit breaker 61,the flow of electrical current (I) will be terminated. The power switch63 is a manual means to also terminate the flow of the electricalcurrent (I), within the integrated connection circuit 18.

[0085] By incorporating the wiring of the laminated glass panel 40 intothe base setting block 47 and providing easy and redundant multiplepanel wiring 90, the present invention eliminates the difficulty ofmaking electrical connections. The hole drilling process into the glasssheet 32 or coated glass sheet 34, prior to lamination, as is typicallydone to expose the bus bars 22 for connection to the alternating currentpower source 19, is eliminated.

[0086] Instead, the present invention uses the metallic tabs 24 andmetal foil 39, described herein that are easily incorporated into theintegrated connection circuit 18. The wiring connections between partsof the integrated connection circuit 18 may have flexible boots (notshown) encasing the connections, and the glazing sealant 23 may be usedto attach the flexible boots to the glass panel peripheral edge 37, soas to minimize mechanical wear and accumulation of moisture. Theflexible boots, with enclosed wiring, may be dressed throughconventional gaskets or sealed with sealant and then terminated inNational Electrical Code (NEC) electrical wiring boxes.

[0087] Typically, the internal integrated connection circuit 18 will becompleted during manufacturing, so as to minimize the need for on-siteelectricians doing system wiring at the time of field installation.Instead, electricians would need to simply verify correct connection andterminate electrical load wiring at the time of field installation.Glaziers would typically be the primary installers of the electricallyconductive heated glass panel 20 by glazing the wiring 90, boots, frames48, and panels 30, 40, which should preserve manufacturing integrity andimprove reliability of the electrically conductive heated glass panels20.

[0088]FIG. 7 shows a cross sectional view of an installation of a singlelaminated glass panel 40 within a second glazing channel 60′. However,it can be appreciated that multiple laminated panels 40, multipleinsulated glass panels 30, or combinations of the panels 30, 40 could berealized in this aspect of the present invention. Also, these panels 20may be used in heated glass, switchable glass, and photovoltaicapplications. In addition, this aspect may be applied to architecturalglazing as well as cladding material.

[0089] As shown, the laminated glass panel 40, along with various partsof the second glazing channel 60′ are disposed on the channel frame 67.A portion of the laminated glass panel 40 is shown being disposed withinthe second glazing channel cavity 59′ and abutting the channel frame 67,wherein the metallic tab 24 extends beyond the periphery of the panel40. Mechanically and electrically disposed on the metallic tab 24 is aspade connector 96, which is mechanically and electrically disposed onan end of channel conductor 27. The channel conductor 27 is shown beingdisposed within the channel conduit 95, which passes through a coupler91 to the conductor block 93. Within the conductor block 93 a second endof the channel conductor 27 may be mechanically and electricallydisposed on the multiple channel wiring 90 (shown in FIG. 6b) or byconventional means in the art on the channel conductors 27 that are partof the interconnect 80 (shown in FIG. 6a).

[0090] Multiple connections, as FIG. 7 illustrates, may be provided ineach of the glazing channels 60, 60′, in order to assure the measure ofredundancy of the electrical connectivity to the panels 30, sincemaintenance and removal of the panels 30 would be tedious and costly.

[0091]FIG. 8a illustrates a cross sectional view at the glass panelperipheral edge 37 of the insulated glass panel 30 where the glass sheet32 and the coated glass sheet 34 are separated by an insulating T-shapedspacer seal 42 (conventionally known as a seal unit) that is disposedaround the periphery 37 therebetween. The insulating T-shaped spacerseal 42 could comprise foamed silicone. In addition, an adhesive sealant36 is disposed on surfaces of the insulating T-shaped spacer seal 42where the insulating T-shaped spacer seal 42 makes contact with theglass sheet 32 and the coated glass sheet 34. The adhesive sealant 36functions to maintain a specified gaseous concentration, preferably atatmospheric pressure, however, any desired pressure may be maintainedwithin a space 38 between the glass sheet 32 and the coated glass sheet34.

[0092] To seal out contaminants and to protect the seal units, a panelframe 48 may be provided that covers the entire seal unit, as it isdisposed around the periphery of the insulated glass panel 30. As sodescribed, the glass edge sealing method may not require that theelectrically conductive coating 44 be removed from the coated glasssheet 34, which may eliminate the need for “edge deletion” andassociated costs.

[0093]FIG. 8b illustrates a cross sectional view at the glass panelperipheral edge 37 of an insulated glass panel 30′ in accordance withthe present invention. The application shown in FIG. 8b is similar tothat shown in FIG. 8a with the exception that the glass sheet 32 and thecoated glass sheet 34 are separated by an insulating E-shaped spacerseal 45 (seal unit) that is disposed around a periphery therebetween.The insulating E-shaped spacer seal 45, having a seal cavity 69, couldcomprise silicone. The seal cavity 69 may be used as a wiring chase forthe placement of interconnecting wiring and for placement of adesiccant, which is used to remove moisture that enters the space 38.The panel frame 48, as shown in FIG. 8a, if so required, may be disposedaround the E-shaped spacer seal 45 of FIG. 8b.

[0094] Some preferred applications of the insulated glass panels 30 ofFIGS. 8a and 8 b would be as architectural panels, such as in glazingsfor commercial buildings, sports stadium skyboxes, sloped glazing inatria, canopies, general fenestration applications, architectural solarpanels and other photovoltaic applications, where the removal ofcondensation on the surface of glass panels would be accomplished byheating the panels to above a dew point.

[0095] If so needed, these applications could utilize the integratedconnection circuit 18 of FIG. 1a, where the current-switch circuit 15would be like that shown in FIG. 2. Due to its design, thecurrent-switch circuit 15 allows the alternating current (I) to beoptically isolated from the control circuit 25, wherein the solid-statecontroller 16 operates the current-switch circuit 15 in the zero-axiscrossing manner. The temperature and/or moisture condition sensors 21would monitor ambient conditions and communicate these conditions to thesolid-state controllers 16, in order for the solid-state controllers 16to command the current-switch circuit 15 to provide the alternatingcurrent power source 19 to the electrically conductive heated glasspanels 20 for the desired heating of the electrically conductive heatedglass panels 20.

[0096] In addition to controlling the heating of the insulated glasspanels 30, the solid-state controllers 16 would monitor the current (I)passing through the conductive strip switches 26 that would be mountedin the insulated glass panels 30. In the event that the conductive stripswitch 26 opens, which could be due to the glass sheet 32 breaking, thecurrent to that electrically conductive heated glass panel 20 would bestopped by the solid-state controller 16, which would remove thepossibility that individuals would be exposed to live electricalhazards.

[0097] A major advantage of using IG panels 30 with low-E coating 44 asthe heating element (as opposed to directly connected resistancecoatings) is the large improvement in energy efficiency, where 25% to30% improvement can be realized, while operating at comparable surfacetemperatures. These results are due to the improved thermal-R-valuesthat result from, for example, double or triple pane IG low-E panels 30.In addition, if the space 38 is filled with argon or krypton, in placeof air, the resulting heating from the IG panels 30 is equivalent tobase board or other electrical resistance heating methods. Addedadvantages of the use of low-E IG panels 30 are an allowance of morehumidity in the room before the onset of condensation and usability ofthe area adjacent to the windows in extremely cold climates.

[0098] Warming shelves 106, 108 and other applications of the panels 30that would be made as those shown in FIGS. 8a, 8 b would have thefollowing advantages: a) the deletion of the coating 44 on the edge 37is unnecessary, b) superior edge protection is provided by the polymericT-shaped seal 42 and E-shaped seal 45, and c) the wire chase provided bythe seal cavity 69 of the E-shaped seal 45 facilitates dressing of thechannel conductors 27.

[0099]FIG. 9 illustrates a cross sectional view at the glass panelperipheral edge 37 of the laminated glass panel 40, in accordance withthe present invention. The electrically conductive coating 44 isdeposited onto a major surface 33 of a glass sheet 32 resulting in theformation of the coated glass sheet 34. In turn, the bus bars 22 aredeposited onto the electrically conductive coating 44.

[0100] Further, the metallic tab 24 is disposed on the bus bar 22, wherea portion of each metallic tab 24 extends beyond the peripheral edge 37of the laminated glass panel 40. Subsequently, the metal foil 39 isdisposed on and in electrical contact with the metallic tab 24, whilealso being disposed on and in electrical contact with the coating 44from the peripheral edge 37 of and within the laminated glass panel 40,up to the sight line 29. To complete an assemblage of the laminatedglass panel 40 thus described, the parts so stated, are brought togetherwith the glass sheet 32 while the interlayer 46 of polymeric material isdisposed therebetween. The interlayer 46 of polymeric material maycomprise polyvinyl butyral (PVB).

[0101] Some of the preferred applications of the present invention thatwould use the laminated glass panels would be as heated glassapplications in vehicles, aircraft, vessels, and the like, where theremoval of condensation and moisture could be achieved on windows,mirrors, and glass parts.

[0102] Photovoltaic laminated panels, which absorb light energy inphotosensitive material that is disposed on the coated glass sheet 34,pass the absorbed energy through the bus bars 22 and metallic tabs 24,in a way similar to that of the present invention.

[0103] Another application of a laminated panel 40 would be as anautomotive rear window defogger where the panel 40 would replace theindividual heater wires. The present invention would provide aninvisible, faster, and more even heater replacement for the currentheaters.

[0104] Further, results from testing indicate that when the panels 30,40 of the present invention are used in various applications thatcurrently use coil, wire type, and parallel resistance heaters, 40% lessenergy is required to power the panels 30, 40. This is due in part tothe low-E properties, the placement of the coating 44, and theuniformity of the coating. Rear window defoggers and cooking heatingelements benefit from this coating heater design.

[0105] In addition to glass substrate material, it has also been foundthat the panels 30, 40 of the present invention may be realized by theuse of ceramic and glass-ceramic substrate materials. The coating 44,bus bars 22, and metallic tabs 24 are deposited equally as well as onglass and that certain applications, for example, cooking and warming,may realize aesthetic and cost benefits from the use of ceramic andglass-ceramic materials.

[0106] The laminated glass panels 40, as shown in FIG. 9, could beapplied where the integrated connection circuit 18 that is shown in FIG.1a, would use moisture and temperature condition sensors 21 to sendsignals (S) to the solid-state controllers 16, which in turn wouldcommunicate with the current-switch circuit 15. The result of thecurrent (I) flowing through the electrically conductive heated glasspanel 20 is to heat the glass and mirrors, so as to remove moisture andcondensation from the electrically conductive heated glass panel 20.

[0107] In addition, through the use of the solid-state controller 16,varying power levels could be provided to achieve functions likedefogging and deicing, where more power is provided for deicing. Thevoltage and current condition sensors 21 may also be applied to senseglass breakage by the use of the conductive strip switches 26. With thepresent invention, the solid-state controller 16 may be used in avehicle to control various electrically conductive heated glass panels20 having a variety of sizes and geometries to maintain, for example,all such glass panels 20 at one temperature or each glass panel 20 at adifferent temperature.

[0108] With the current-switch circuit 15 being operated in thealternating current, zero-axis crossing manner, those vehicles, forexample, automobiles, that only have a direct current power source,would require conventional inverter circuitry to generate thealternating current that is needed for the current-switch circuit 15.However, other vehicles and vessels, for example, emergency vehicles,fire trucks, ships, yachts, trains, and large earth moving vehicles, mayhave on-board alternating current power sources 19 that would notrequire the conventional inverter circuitry and could be connecteddirectly to the present invention's integrated connection circuit 18, asillustrated in FIG. 1a.

[0109] Further applications of the laminated glass panels 40 would havethe present invention being utilized in commercial refrigerator/freezerdoor applications, where the removal of condensation on the surface ofthe laminated glass panel 40 that is exposed to the cold air inside ofthe refrigerator or freezer would be accomplished by heating thelaminated glass panel 40 to a temperature above the dew point. Theseapplications would utilize the integrated connection circuit 18 of FIG.1a, the laminated glass panel 40 of FIG. 9, and the triac circuit 17 ofFIG. 2.

[0110] Temperature and/or moisture condition sensors 21 would monitorambient conditions and communicate these conditions to solid-statecontrollers 16, which in turn command the current-switch circuit 15 toconduct alternating current to the laminated glass panels 40, whichwould subsequently heat the laminated glass panels 40, thus removingcondensation or other forms of moisture.

[0111] In addition to controlling the heating of the laminated glasspanels 40, the solid-state controllers 16 would monitor current (I)passing through the conductive strip switches 26 that are mounted oncoated glass sheets 34. In the event that a conductive strip switch 26opens, which could be due to a particular laminated glass panel 40breaking, the current to that laminated glass panels 40 would bedisrupted, hence removing the possibility that individuals would beexposed to live electrical hazards. Since the solid-state controller 16would be monitoring the conductive strip switches 26, it would sensethat a particular conductive strip switch 26 had opened and would alertnecessary personnel.

[0112] Two problems that arise with supplying electrical current tobanks of refrigerator/freezer doors that the use of solid-statecontrollers 16 would overcome, are: (1) the precise electrical controlof the uniform low E heating coatings 44 that should result in uniformheating of the laminated glass panels 40 of the banks ofrefrigerator/freezer doors and (2) the synchronization of thecurrent-switch circuit 15 switching to overcome peak current problems.

[0113] Because a bank of laminated glass panels 40 presents a largedemand for power, solid-state controllers 16 would be used to providepower demand-based control to avoid brown outs, power peak monitoring tocontrol kilowatt usage costs, and “turning back” of the supply of powerin off-hours to also control kilowatt usage costs. Condition sensors 16,other than temperature and moisture, for example, voltage and current,would be used to signal the solid-state controllers 16 for commanding avariety of conventional operations.

[0114] Note that the use of electronic controls with both IG panels 30and laminated panels 40 of the present invention result in higherheating efficiency while using less power than conventional panels andwhile providing greater safety. This is due to the use of low emissivitycoated glass that places the heating element in an advantageous positionwith respect to the user and items being heated, and provides for lesselectrical noise generation.

[0115]FIG. 10a, which involves the deposition of the bus bars 22 ontothe coating 44 that is deposited on the glass sheet 32, illustrates adiagramatic view of a circularly rotating heating head and maskapparatus 50 in accordance with an aspect of the present invention. Thebus bars 22, as shown in FIGS. 1a, 1 b, and 1 c, function toelectrically connect the metallic tabs 14, which are the exteriorconnections for delivering the electrical current (I) to the coating 44of the glass panels 20. As a result, the current (I) supplied to thecoating 44 causes the coating 44 to dissipate heat.

[0116]FIG. 10a illustrates the deposition of bus bars 22 on the coatedglass sheet 34, which may be deposited through the use of improveddeposition methods in accordance with further aspects of the invention.For example, the coating deposition may comprise chemical vapordeposition, where the coating 44 is deposited onto the dielectricsubstrate material, for example, the glass sheet 32. The coated glasssheet 34 may then be exposed to a preheat zone 70 upstream and, if “edgedeletion” is required, the conveyor 88 transports the coated glass sheet34 to a circular edge mask 66. While moving within the circular edgemask 66, a first area 92 of the coated glass sheet 34 is heated by acoating heater 76. The coating heater 76 could comprise, as examples, anoxyacetylene burner, a plasma device, an electric arc gun, or a flamespray gun.

[0117] In the case of the electric arc gun, electrical current isconducted through metal wires that are fed into the electric arc gun inorder to melt the metal wire. In all of the alternatives for the coatingheater 76, very high velocity airflow entrains and accelerates themolten metal particles to ensure good adhesion.

[0118] In the first area 92, temperatures up to and about 1300 degreesFahrenheit may be attained in order to heat, thermally shock, andevaporate the electrically conductive coating 44.

[0119] Edge deletion may also be achieved without the use of the edgemask 66. This may be accomplished through precise placement of the heatand thermal control and set up of the coating heater 76, such that thecoating 44 is precisely thermally shock heated and evaporated. Either ofthese processes may be required for the IG panels 20 (shown in FIGS. 8aand 8 b) to establish a better surface for sealing in the atmospherewithin the space 38.

[0120] By either method, a residue of the electrically conductivecoating 44 is formed and may, subsequently, be removed by a coatingremover 68, which, for example, may be a buffer or a burnishing tool.The coating remover 68 may be required for the IG panels 20 (shown inFIGS. 8a and 8 b) to establish a better surface for sealing in theatmosphere within the space 38. As a result, this process produces adeleted edge 71, as shown in FIG. 10a.

[0121] Next, as FIG. 10a also illustrates, the coated glass sheet 34 isconveyed to a circular inner mask 72 and a circular outer mask 74 wherea second area 94 of the coated glass sheet 34 is defined therebetweenand where dimensional control of the placement, thickness, tapering, andheight of the bus bars 22 is achieved. First a reducing flame 78 heatsthe second area 94 in a stoichiometric atmosphere, where oxidation of amolten metal 64 is controlled during bus bar 22 deposition, while notfracturing or de-tempering the coated glass sheet 34. The reducing flame78 could comprise oxyacetylene or hydrogen. As a result, the second area94 is taken to a temperature of about 500 degrees Fahrenheit.

[0122] Subsequently, a metal feeding and heating device 62, which issupplied by gas one 82, gas two 84, and gas three 86 feeds conductivemetal 56, preferably in the form of a wire (however, the conductivemetal could be fed as a powder or in other forms), melts the conductivemetal 56, and then propels and impinges particles of the molten metal 64in a predetermined manner, for example, a uniform manner, onto thesecond area 94. The metal feeding and heating device 62 preferablycomprises a plasma gun, while the three gases 82, 84, and 86 preferablycomprise oxygen, air, and acetylene, and the conductive metal 56preferably comprises copper.

[0123] This operation results in the bus bars 22 being uniformly formedon, and adhering strongly to, the electrically conductive coating 44.The formation of the bus bar 22 occurs, for example, near the glasspanel peripheral edges 37, before the laminated glass panel 40, as shownin FIG. 9, or the IG panels 30 and 30′, as shown in FIGS. 8a and 8 b,are fully assembled.

[0124] Added advantages of the circularly rotating heating head and maskapparatus 50 are that its rotation and size allow for: (1) dissipationof built up heat, (2) the excess molten metal 64 to be scraped, brushed,or blown clean, and (3) accurately depositing the molten metal 64 ontothe electrically conductive coating 44 so as to shape the bus bars 22.The shaping of the bus bars 22, if so preferred, may be tapered towardthe glass panel peripheral edge 37 and/or tapered on end, as well.

[0125] The result of these steps is the production of conductive metalbus bars 22 that are uniformly deposited and have good mechanicalbonding to the electrically conductive coating 44, which makes themrobust for external connectivity. In addition, the bus bars 22 possessgood ohmic conductivity themselves and also in relation to theelectrically conductive coating 44.

[0126] Further, the circularly rotating heating head and mask apparatus50 accurately controls the thickness of the resulting copper bus bars22, so that the thicker the bus bars 22, as shown in FIGS. 1a and 1 b,the higher the electrical current (I) that can be conducted through thebus bars 22, which consequently provides higher electrical current (I)that can be supplied to the glass panel 20 or plurality thereof. In thecase of electrically conductive heated glass panels 20, the higher theelectrical current (I) that can pass through the electrically conductiveheated glass panels 20 the higher the heat that can be dissipated by theelectrically conductive heated glass panels 20. Also, the use of copperas the bus bar 22 material is less expensive than silver. However, thepresent invention may be practiced where silver or other conductivemetals comprise the bus bar materials.

[0127] An additional advantage of this process is that it allows the busbars 22 to be deposited after thermal tempering of the electricallyconductive heated glass panels 20. Although not wishing to be bound byany theory, it is believed that there is no alloying of the molten metal64, for example, copper, with the electrically conductive coating 44,since the electrically conductive coating 44 is highly chemicallyinactive and stable. The electrically conductive coating 44 preferablycomprises tin oxide. It has also been found that the deposition of theconductive metal, for example, copper, bus bar 22 will also adherestrongly to the coating 44 as it is disposed on ceramic or glass-ceramicsubstrates.

[0128] To form the bus-bars 22, the circularly rotating heating head andmask apparatus 50 of the present invention does not use an aqueoussolution. Instead, it heats and shapes the bus bars 22 onto theelectrically conductive coating 44 by melting the conductive metal 56,and imparting pressure, through the gasses one 82, two 84, and three 86,to impinge, at a high velocity, the molten metal 64 onto the heated andmasked second area 94 on the electrically conductive coating 44.

[0129] Further, the metallic tabs 24 may then be readily conductivelyaffixed to external wiring 27 as part of the integrated connectioncircuit 18. The panel 20, as so constructed may be used for cookingappliances, for example, a heating (conventionally known as a “burner”)element. The bus bar deposited panel 20, as thus described, may also beused to form IG panels 30, laminated panels 40, or combination thereof.

[0130] Illustrated in FIG. 10b is an inline heating head and maskapparatus 50′ that is also capable of edge deletion and capable ofdisposing the bus bar 22 on the coated glass sheet 34. If edge deletionis required, the coated glass sheet 34 moves on the conveyor 88 so thatthe edge of the coated glass sheet 34: a) may be preheated in thepreheat zone 70, b) be thermally shocked at the first area 92, and c)have the coating 44 removed by a coating remover 68, which, for example,may be a buffer or a burnishing tool, d) is formed into the deleted edgearea 71. This process is the same as that described above for thecircularly rotating heating head and mask apparatus 50, with theexception that an inline edge mask 66′ replaces the circular edge mask66.

[0131] Note that edge deletion may also be achieved by the apparatus 50,50′ without the use of the edge masks 66, 66′. This may be accomplishedthrough precise placement of the heat and thermal control, and set up ofthe coating heater 76, such that the coating 44 is precisely thermallyshock heated. This process may be required by the IG panels 30 (shown inFIGS. 8a and 8 b) to establish a better surface for sealing in theatmosphere within the space 38.

[0132] As the coated glass sheet 34 moves further on the conveyor 88,the bus bar 22 can be disposed on the coating 44 in the same mannerdescribed above for the circularly rotating heating head and maskapparatus 50, except that an inline inner mask 72′ and an inline outermask 74′ are used instead of the circular masks 72 and 74. The inlinemasks 72′ and 74′ can also result in the same precise formation of thebus bars 22 as the circularly rotating heating head and mask apparatus50.

[0133] A variant of the inline heating head and mask apparatus 50′ is adual belt based inline heating head and mask apparatus 140 that is shownin FIGS. 10c-10 e. The apparatus 140 comprises: 1) a work piece inputarea 160, comprising a first belt 144, first rollers 158, and a firstspeed and tension adjuster 178, 2) a second belt 142, second rollers156, and a second tension adjuster 176, and being driven by second motor154, second motor pulley 172, motor belt two 174, 3) a third belt 146,third rollers 162, and a third tension adjuster 182, and being driven bythird motor 152, third motor pulley 166, and motor belt three 168, 4) athermo spray area 150, 5) a work piece output area 170, comprising afourth belt 148, fourth rollers 162, and a fourth speed and tensionadjuster 184, and 6) an overspray removing device 190.

[0134] This inline apparatus 140 may also be practiced by employingother means for driving the belts, for example, sprocket gears andchains, racks and pinions, and the like, while still remaining withinthe scope and spirit of the present invention.

[0135] In operation, an incoming coated glass sheet 34 is conveyed bythe first belt 144 to an adjustable stop 188. Note that the coating 44is on a side of the coated sheet 34 that will make direct contact withthe second belt 142. Note also that the stop 188 is capable ofadjustment so as to position varying sizes of coated glass sheets 34 atthe end of the first belt 144.

[0136] Upon reaching the stop 188, the coated glass sheet 34 ispositioned inline with a roller area 198 that is between the second belt142 and the third belt 146 while centrally spanning the second belt 142.The width of the second belt 142 is chosen to be less than the width ofthe sheet 34 so as to allow the second belt 142 to act as a mask whileexposing opposite edges of the coating 44 on the sheet 34.

[0137] Subsequently, a cylinder 199 causes an indexer 186 to urge thesheet 34 into the roller area 198 between second belt roller 156 b andthird belt roller 162 a so as to convey the sheet 34 in a directiontoward the thermo spray area 150. Note that the linear speeds of thebelts 142, 146 being adjusted to be approximately the same by therespective adjusters 176, 182 and that the sheet 34 is held in place bya clamping force that is imposed by the opposing belts 142, 146. Thecylinder 199 may be realized by any means that is conventional in theart to properly push or pull the indexer 186.

[0138] Upon reaching the thermo spray area 150, the exposed oppositeedges of the sheet 34 may be heated by at least one reducing flame 78(not shown but similar to those illustrated in FIGS. 10a, 10 b)) andimpinged by at least one metal feeding and heating devices 62, so as todispose molten metal 64 onto the opposite edges of the coated sheet 34.The bus bar deposition operation is accomplished in much of the samemanner as that used by the circular and inline heating head and maskapparatus 50, 50′ and results in the deposition of the bus bars 22 atthe opposite edges of the coated glass sheet 32. Ceramic orglass-ceramic sheets may replace the glass sheets.

[0139] Following bus bar deposition in the thermo spray area 150, thesheet 34 is conveyed to a fourth belt 148 having fourth belt rollers 164and fourth speed and tension adjuster 184 and driven by a means (notshown) that is similar to the previously described motor, pulley, andbelt, which in turn conveys the sheet 34 to a work piece output area170. After drop-off of the sheet 34 onto the fourth belt 148, the secondbelt 142 may be exposed to the overspray removing device 190 in order toremove any conductive metal overspray that may have been deposited onthe second belt 142. The overspray removing device 190 may be, forexample, a tank containing a coolant 196 and having an outlet 192 and aninlet 194, where the overspray is removed by thermal shock and scraping.However, the present invention may be practiced where the oversprayremoving device 190 is at least one fan, scraper, or the like.

[0140] The dual belt based inline heating head and mask apparatus 140 isdesigned to produce panels 20 in a fast and simple manner for heatingelements, for example, a so-called fifth burner appliance (like aseparate cooking appliance that would rest on a counter-top) and cooktopheating elements. In these applications a high speed, low cost processis advantageous and this apparatus 140 is capable of achieving thosegoals while producing high quality electrical connectivity to thecoating 44. However, this apparatus 140 may be used for producing panelsother than burner elements, for example, photovoltaic applications.

[0141] In the present invention, the masks 66, 66′, 72, 72′, 74, 741,142 may comprise steel with a layer of chrome plating disposed on thesteel. This has been found to inhibit the adhesion of copper and othermetals to the masks 66, 66′, 72, 72′, 74, 74′, 142 thus allowing asimple spring loaded scraper to continually clean the overspray from themasks 66, 66′, 72, 72′, 74, 74′, 142 during production of the bus bars22. This operation allows the overspray and dust of the conductive metal56 to be collected and re-sold. The present invention may furtherdeposit soft electrically conductive materials (not shown) that includemetal and metal oxides, often in combination with each other, onto thebus bars 22, following bus bar deposition to the coating 44.

[0142] Examples of the soft conductive materials are silver basedsystems like (metal oxide/silver/metal oxide) and variants includingdouble silver stacks and indium-tin-oxide (known as ITO.) All constructsof the bus bars 22, metallic tabs 24 and the panels 20 that have beendisclosed herein apply with the addition of the deposition of the softconductive materials.

[0143] The soft coatings may be deposited in a vacuum deposition processlike that produced by DC Magenetron Sputtering after the bus bars 22 aredeposited on the coatings 44. For example, these soft coatings may becopper traces that would conduct electrical current to electricalcomponents that would be mechanically attached to the glass sheet 32 orcoated glass sheet 34. An example electrical component would be acapacitive moisture sensing unit on the sheet 32, 34.

[0144] Another example of the present invention being used as anappliance is illustrated in FIG. 11, which is a perspective view of awarming oven 100. The warming oven 100 would have at least a firstwarming shelf 106, however, FIG. 11 shows the warming oven 100 with thefirst warming shelf 106 and an accompanying second warming shelf 108.The warming shelves 106, 108 would comprise insulated glass panels 30,wherein the bus bars 22 and metallic tabs 24 have been formed thereon inthe manner described above in the present invention. The control of thewarming of items placed in the warming oven 100 would be accomplished bythe oven controls 112, which would comprise the elements of theintegrated connection circuit 18.

[0145] An added advantage of the use of the insulated glass panel 30 inthe warming oven 100 is that the insulated glass panel 30 affordsphysical separation between the coating 44 and the item beingthermo-conductively warmed, wherein capacitive coupling and leakagecurrents from the heating coating to the item being heated are virtuallyeliminated, thus eliminating electrical shock potential and sparkignition for a fire.

[0146]FIG. 12 illustrates another aspect of the present invention, wherethere is shown an oven door panel 110, which is mounted in an oven doorframe 122 for viewing food items being cooked in an oven interior 124.This aspect of the present invention utilizes an assembly comprising atemperature sensing means, for example, rapid measurement of the voltageacross the bus bars 22 (as discussed above in conjunction with acontroller 16) or a temperature switch 118 disposed on the exterior ofthe coated glass sheet 34, with bus bars 22, for example, copper,disposed on the coating 44 (in the manners described above for thepresent invention), and a thermally activated light scattering material116 disposed on the coating 44. The light scattering material 116 maycomprise, for example, ThermoSEE™ which is commercially available fromPleotint LLC, West Olive, Mich.

[0147] The temperature switch 118 would be part of the integratedconnection circuit 18 for the oven (not shown) and would function tosense the exterior temperature of the oven door panel 110. If theexterior temperature of the oven door panel 110 would exceed a setpointtemperature, the temperature switch 118 would electrically open, whichin turn would cut off current (I) to conventional oven heating elements(not shown), so as to eliminate the possibility of burning a person thatmight touch the exterior surface of the oven door panel 110.

[0148] The bus bars 22, which may be connected to and controlled by theintegrated connection circuit 18, by way of the metallic tabs 24 thatare disposed on the bus bars 22 and electrically connected to thechannel conductors 27, are used to precisely control the heating of theoven door panel 110 so as to precisely control the opacity of the lightscattering material 116, which is opaque at room temperature and up to atemperature of about 150 degrees F., at which temperature and above, thelight scattering material 116 becomes essentially transparent. As aresult, the contents of the oven interior 124 can be viewed from outsideof the oven under the precise control of the integrated connectioncircuit 18 of the present invention or by conventional means in the art.

[0149] In accordance with the provisions of the patent statutes, theprinciples and modes of operation of this invention have been describedand illustrated in its preferred embodiments. However, it must beunderstood that the invention may be practice otherwise thanspecifically explained and illustrated without departing from its spiritor scope.

What is claimed is:
 1. An apparatus for depositing a metal bus bar,comprising: a metal feeding and heating device; an outer mask; and aninner mask; said metal feeding and heating device capable of feeding,melting, and impinging at high velocity a molten metal into electricalcontact with an electrically conductive coating that is disposed on asheet of dielectric substrate material, said molten metal beingdeposited in an area on said electrically conductive coating that isdefined between said outer mask and said inner mask, thus forming atleast a portion of said metal bus bar.
 2. The apparatus of claim 1,further comprising a source of a reducing flame that is capable ofheating said coating in said area.
 3. The apparatus of claim 1, furthercomprising: an edge mask; a coating heater, said coating heater capableof heating another area of said coating that is defined by said edgemask along an edge of said dielectric substrate sheet; and a coatingremover, said coating remover capable of removing said heated coating.4. The apparatus of claim 3, wherein said edge mask comprises acircularly rotating mask.
 5. The apparatus of claim 3, wherein said edgemask comprises an inline mask.
 6. The apparatus of claim 1, wherein saiddielectric substrate sheet comprises glass.
 7. The apparatus of claim 1,wherein said dielectric substrate sheet comprises ceramic.
 8. Theapparatus of claim 1, wherein said dielectric substrate sheet comprisesglass-ceramic.
 9. The apparatus of claim 1, wherein each of said innerand outer masks is comprised of a circularly rotating mask.
 10. Theapparatus of claim 1, wherein each of said inner and outer masks iscomprised of an inline mask.
 11. The apparatus of claim 1, wherein saidmetal feeding and heating device comprises a plasma gun.
 12. Theapparatus of claim 1, wherein said metal comprises copper or silver. 13.An apparatus for depositing a metal bus bar, comprising: at least twoconveyor belts operating in a parallel spaced apart manner, the width ofat least one of said belts being less than the width of a sheet ofdielectric substrate material so as to expose opposite edges of saidsubstrate sheet; an indexer capable of urging said substrate sheetbetween said belts, said belts being capable of applying forcibleclamping and conveying motion to said substrate sheet; and at least onemetal feeding and heating device, wherein said metal feeding and heatingdevice impinges at high velocity a molten metal into electrical contactwith a conductive coating disposed on said dielectric substrate sheet insaid exposed edges, thus forming at least a portion of said metal busbar as said dielectric substrate sheet is conveyed past said metalfeeding and heating device by said at least two conveyor belts.
 14. Theapparatus of claim 13, further comprising an overspray removing device,wherein an overspray of said molten metal is removed from said beltsfollowing bus bar deposition.
 15. The apparatus of claim 13, whereinsaid metal feeding and heating device comprises a plasma gun.
 16. Theapparatus of claim 13, wherein said metal comprises copper or silver.17. The apparatus of claim 13, wherein said electrically conductivecoating comprises a doped metal oxide and said dielectric substratesheet comprises glass, ceramic, or glass-ceramic.
 18. The apparatus ofclaim 13, further comprising at least one reducing flame, wherein saidreducing flame preheats said exposed edges prior to bus bar formation.19. A method of depositing a metal bus bar on a sheet of dielectricsubstrate material having an electrically conductive coating disposedthereon, comprising: masking an area on said substrate sheet; heatingsaid area with a reducing flame; feeding a metal into a metal feedingand heating device; melting said metal to form a molten metal; andimpinging said molten metal at high velocity into electrical contactwith said electrically conductive coating in said area, thus forming atleast a portion of said bus bar.
 20. The method of claim 19, whereinsaid metal feeding and heating device comprises a plasma gun.
 21. Themethod of claim 19, wherein said electrically conductive coatingcomprises a doped metal oxide and said substrate sheet comprises glass,ceramic, or glass-ceramic.
 22. The method of claim 19, wherein at leastone circularly rotating mask is utilized to mask said area.
 23. Themethod of claim 19, wherein at least one inline mask is utilized to masksaid area.
 24. The method of claim 19, wherein said reducing flamecomprises hydrogen.
 25. The method of claim 19, wherein said reducingflame comprises oxyacetylene.
 26. The method of claim 19, wherein saidheating of said area is provided in a stoichiometric atmosphere whereoxidation of said molten metal is controlled, while not fracturing orde-tempering said substrate sheet.
 27. The method of claim 19, whereinsaid conductive metal comprises copper or silver.
 28. A method ofdeleting a conductive coating, said coating being disposed on a majorsurface of a sheet of dielectric substrate material, comprising: heatingan area on an edge of said substrate sheet using a coating heater;evaporating said coating in said area with said coating heater; forminga residue of said coating; and deleting said residue with a coatingremover.
 29. The method of claim 28, further comprising preheating ofsaid area prior to heating.
 30. The method of claim 28, furthercomprising, prior to heating, masking of said area with an edge mask.31. The method of claim 28, wherein said coating heater comprises anoxyacetylene heater.
 32. The method of claim 28, wherein said coatingheater comprises a plasma device.
 33. The method of claim 28, whereinsaid evaporating comprises thermally shocking said conductive coating insaid area.
 34. The method of claim 28, wherein said coating removercomprises a burnishing tool.
 35. The method of claim 28, wherein saidcoating remover comprises a buffer.
 36. The method of claim 28, whereinat least-one circularly rotating mask is utilized in heating said area.37. The method of claim 28, wherein at least one inline mask is utilizedin heating said area.
 38. A method of depositing conductive metal busbars on a sheet of dielectric substrate material having an electricallyconductive coating disposed thereon, comprising: urging said substratesheet between two conveyor belts, thus exposing at least one edge onsaid substrate sheet; conveying said substrate sheet toward a heatinghead and mask device; melting conductive metal in said heating device toform a molten metal; and impinging said molten metal at high velocityinto electrical contact with said electrically conductive coating insaid at least one edge on said substrate sheet, thus forming at least aportion of said bus-bar.
 39. The method of claim 38, wherein saidimpinging utilizes a plasma gun.
 40. The method of claim 38, whereinsaid electrically conductive coating comprises a doped metal oxide, andsaid substrate sheet comprises glass, ceramic, or glass-ceramic.
 41. Themethod of claim 38, wherein said conductive metal comprises copper orsilver.